Reflex-reflecting compositions containing glass beads and non-metallic flake pigments

ABSTRACT

COATING COMPOSITIONS WHICH PROVIDE REFLEX-REFLECTING PROPERTIES COMPRISING (A) A BINDING VEHICLE, (B) TRANSPARENT GLASS BEADS AND (C) NON-METALLIC FLAKE PIGMENT PARTICLES HAVING A REFLECTIVE MIRROR-LIKE FINISH.

United States Patent O REFLEX-REFLECTING COMPOSITIONS CONTAIN- ING GLASSBEADS AND NON-METALLIC FLAKE PIGMENTS Charles E. Searight, Steven H.Brasfield, Sr., and Thomas E. McCraney, Jackson, Miss., assignors toFerro Corp., Cleveland, Ohio N Drawing. Continuation of abandonedapplication Ser. No. 138,831, Apr. 29, 1971. This application Dec. 1,1972, Ser. No. 311,095

Int. Cl. C08g 51/28 US. Cl. 260--33.6 R 6 Claims ABSTRACT OF THEDISCLOSURE Coating compositions which provide reflex-reflectingproperties comprising (a) a binding vehicle, (b) transparent glass beadsand (c) non-metallic flake pigment particles having a reflectivemirror-like finish.

This is a continuation of application Ser. No. 138,831, filed Apr. 29,1971, now abandoned.

SUMMARY OF THE INVENTION The present invention relates to improvedreflex-reflecting compositions. In general, it relates to a liquidcoating composition which upon application to a surface providesreflex-reflecting properties to the surface. More particularly, itpertains to compositions containing non-metallic flake pigment particleshaving a reflective mirror-like finish, which particles when combinedwith transparent glass beads and suitable binding vehicle exhibitreflexreflecting properties.

BACKGROUND OF THE INVENTION Heretofore, various coating compositionshave been disclosed and/or used for providing reflex-reflectingproperties or characteristics to a surface, for example, a highway signor marker. In the prior art, reflex-reflecting surfaces have beenobtained by various methods and by employing various coatingcompositions. US. Pat 3,251,704, for example, discloses either directlyor by incorporation by reference several prior art approaches forproviding a surface which exhibits reflex-reflecting properties. Oneproblem commonly encountered with such prior art approaches has beenachieving the reflex-reflecting characteristics while at the same timeretaining or providing a true color of the coated surface. For example,one commonly employed prior art method of providing a surface withreflex-reflecting properties consists of applying to a surface a coatingcomposition comprising finely divided reflective metallic (e.g.,aluminum) flake powder in combination with glass beads and a suitablebinding vehicle. With such metallic flake pigment containing coatingcompositions, the daytime color of the coated surface tends to appeargrey rather than white and the nighttime color tends to appear silver.Thus, there has existed heretofore a need for a coating compositionwhich, when applied to a surface, would not only make the surfaceexhibit reflexreflecting properties but also permit the coated surfaceto exhibit both true daytime color and true nighttime color.

DESCRIPTION OF THE INVENTION We have discovered a coating compositionwhich, when applied to a surface, provides reflex-reflecting propertiesand also permits the coated surface to exhibit both true daytime colorand true nighttime color. The coating composition of the presentinvention is a normally liquid material consisting essentially of (a) asuitable binding vehicle, (b) transparent glass beads and (c)non-metallic flake pigment particles.

The non-metallic flake pigment particles employed in the compositions ofthe present invention have not been employed heretofore for supplyingthe reflecting characteristics in a reflex-reflecting composition. Thenonmetallic flake pigment particles suitable for use in the inventionhave a particle size in the range from about 2 to about 40 microns, anda thickness of about 0.3 to about 0.7 microns. The particles arechemically inert and heat resistant but are relatively fragile and careshould be taken when preparing the compositions of the present inventionso that the particles are not unduly shattered. These particles are alsosometimes referred to as synthetic pearl pigments and comprise micaflakes with a titanium dioxide coating which manifests a reflectivemirror-like finish. Such pigments are currently available in white, goldand iridescent red color, from the Mearl Corporation, New York, N.Y.

The transparent glass beads or microspheres employed in the compositionsof the present invention are well known in the art and have beenemployed heretofore in other reflex-reflecting compositions. In order toobtain optimum reflex-reflecting characteristics, coatability,dispersion and suspension in the binding vehicle, the transparent glassbeads should preferably have a refractive index of at least about 1.8,preferably about 1.9 or higher to obtain optimum reflex-reflectingcharacteristics, when viewed under ambient dry conditions. Thetransparent glass beads may be either transparent white or transparentcolored, for example, yellow.

The binding vehicle employed in the compositions of the presentinvention is generally a varnish or varnishlike material. Such bindingvehicles are known in the art and per se form no part of the presentinvention. Such binding vehicles generally include oil and spirit resinvarnishes as well as lacquers, which provide adequately durabletransparent film coatings when coated and dried. Such binding vehiclesgenerally comprise a mixture of non-volatile film forming bindingmaterial (i.e., varnish solids) and volatile solvent material whichimparts fluidity and which evaporates during drying. Alkyd resinvarnishes are particularly preferred. The liquid binding vehicle alsogenerally includes small amounts of an anti skinning agent which agentsare well known in the varnish art to prevent or minimize the formationof a surface skin upon exposure to the atmosphere. Minor amounts ofother optional ingredients may also be added, for exam: ple, colloidalsuspending agents may be used to assist in producing a more stablesuspension of the transparent glass beads and the non-metallic flakepigment particles. Varnish dryers such as metal napthenates (e.g.,cobalt, lead, and/ or manganese napthenates) can also be used.

In one embodiment of the present invention, other additional pigmentssuch as titanium dioxide coated glass beads are included in amounts upto about 10 wt. percent of the composition in order to provideadditional color.

The relative amounts of the ingredients of the compositions of thepresent invention will, of course, vary depending upon the particularingredients employed as Well as such factors as the specific size of thetransparent glass beads, etc.; but in any event suitable amounts can bereadily determined by those skilled in the art in any given instance. Ingeneral, it has been found that about 1 to about 10 parts on a weightbasis of non-metallic flake pigment particles for each 400 parts ofglass beads results in satisfactory compositions. The bead volumeconcentration (bvc) is known in the art to be percent ratio of thevolume of the transparent glass beads to the summation of the volume ofthe transparent glass beads plus the volume of the pigment plus thevolume of the binding vehicle solids (on a dry basis). The compositionsof the present invention will generally have a bvc value within therange of about 50 to about 90 percent.

The compositions of the present invention are prepared by firstpreparing a mixture of the transparent glass beads and the bindingvehicle. To that mixture, the non-metallic flake pigment particles areadded and stirred with a minimum of agitation. The resulting compositionmay be applied to a base surface by brush, knife coat, spray methods andthe like. The resulting coated surface exhibits reflexreflectingcharacteristics and also manifests both daytime color and nighttimecolor which are truer in the sense that whites look and stay white andyellows look and stay yellow, as compared for example, to prior artcompositions containing metal flake pigments.

The present invention may be further understood by reference to thefollowing illustrative example.

EXAMPLE In this example a coating composition of the present inventionis prepared having the following ingredients:

Ingredient: Percent by weight Binding vehicle 23.9 Transparent glassbeads (-170 mesh, 1.91

refractive index) 64.5 Non-metallic flake pigment particles 1.6 Whitecoated beads 9.7 Metal naphthenate drier .2 Anti-skinning agent .1

The above coating composition of this example is prepared by firstpreparing the binding vehicle by mixing about 44% polyarnide modifiedalkyd resin (Burnox 3540) with about 56% mineral spirits and heating,with agitation, to about 100 F. to dissolve the resin. The resultingmixture is allowed to cool to about 70 F. and upon cooling the mixtureforms a gel. To the binding vehicle, the transparent glass beads, themetal naphthenate drier, the anti-skinning agent, and the white coatedbeads are added. The white coated beads are an optional, preferred,ingredient which adds white pigment to the coating composition withoutchanging the essential reflex-reflecting properties of a surface coatedwith the composition. The white coated beads may be obtained by tumblingtransparent glass beads (170 mesh, 1.51 refractive index) in a mixingapparatus and coating with a mixture of titanium dioxide, acetone andacrylic lacquer. The nonmetallic flake pigment particles are thencarefully stirred into the mixture and the resulting composition isready for use.

When the composition of the example is applied, for example, by brushingonto a surface, the coated surface shortly thereafter dries andmanifests reflex-reflecting properties. Moreover, such a coated surfaceappears true white during both daylight and nighttime viewing.

While the present invention has been described by reference to the abovespecification including an illustrative example, various modificationswithin the spirit and scope of the invention will be apparent to thoseskilled in the art.

What is claimed is: 1. A coating composition which, upon application toa surface, provides reflex-reflecting properties to said surface, saidcomposition consisting essentially of (a) a binding vehicle, (b)transparent glass beads and (c) nonmetallic flake pigment particleshaving a reflective mirrorlike finish;

said flake pigment particles comprising mica flakes having on theirsurface a coating of titanium dioxide;

said non-metallic flake pigment particles constituting about 1 to 10parts on a weight basis for each 400 parts of glass beads.

2. A composition as defined by claim 1 wherein said pigment particlesare essentially flat flakes having a particle size about 2 to about 40microns and a thickness of about 0.3 to about 0.7 microns.

3. A composition as defined by claim 1 wherein said pigment particlesare synthetic pearl pigments.

4. A composition as defined by claim 1 wherein said beads have arefractive index of at least about 1.9.

5. A composition as defined by claim 1 wherein said binding vehiclecomprises a mixture of polyarnide modified alkyd resin and mineralspirits.

6. A composition as defined by claim 1 containing as an additionalingredient up to about 10 wt. percent of an additional pigmentcomprising titanium dioxide coated glass beads.

References Cited UNITED STATES PATENTS 3,251,404 4/1966 Nellessen106-193 3,475,191 10/1969 Lodge et al. 106-288 3,087,828 4/1963 Linton106291 3,036,928 4/1962 Poole 117-33 2,933,989 4/1960 Adrian 941.53,288,618 11/1966 De Vries 106148 ALLAN LIEBERMAN, Primary Examiner R.ZAITLEN, Assistant Examiner US. Cl. X.R.

